Of the 10 men accused of carrying out the deadly Paris terror attacks, he was the only one at large. Investigators think Abdeslam may have been the driver of the black Renault Clio that dropped off three suicide bombers near the Stade de France, one of the attack sites.
They also think he wore a discarded suicide belt found on a Paris street
after the attacks, a belief based on sweat on the belt that matched Abdelslam's DNA, a source close to the investigation told CNN.
The inability to apprehend the Belgian-born French citizen was particularly irksome because police stopped him after the November 13 attacks
but did not detain him.
He is believed to have called friends to take him to Belgium after the attacks. They passed through police checkpoints, but Abdeslam had not yet been identified as a suspect and they were allowed to continue on their way.
Captured in Molenbeek
He proved elusive until Friday, when authorities captured him after a shootout in Molenbeek, an impoverished suburb of Brussels, Belgium.
Armed and heavily protected police converged on the area and arrested Abdeslam at a residence.
Three explosions were heard there later Friday, CNN French affiliate BFMTV reported, though it wasn't clear if those were controlled blasts or part of a continuing operation.
Abdeslam, a Belgium-born French citizen, was taken alive but wounded, authorities said. He was brought to a hospital after being shot in the leg, CNN Belgium affiliate VTM reported, citing a police source.
Four other people were arrested, including three people in the same family who hid Abdeslam, Belgian Federal Prosecutor Eric Van Eric Van Der Sijpt, said in a press conference.
Authorities believe Abdeslam had been using the apartment as a hideout after the Paris attacks.
His brother died in suicide bombing
The search for Abdeslam had stretched across the world, with authorities thinking he might have fled to Syria. Molenbeek was an area of special interest.
Molenbeek has a heavy Muslim population and is known as a hotbed for jihadists. In the immediate aftermath of the Paris attacks, authorities conducted raids there and detained numerous individuals.
One was Abdeslam's brother, Mohammed Abdeslam, who was later released.
Mohammed Abdeslam told Belgian state broadcaster RTBF that he thinks Salah at the "last minute ... decided to reconsider" carrying out an attack on November 13; the attacks were intended as suicide missions.
One of those who did follow through was another brother, Ibrahim Abdeslam, a suicide bomber who detonated explosives outside a cafe on Paris' Boulevard Voltaire.
On Friday, the Belgian federal prosecutor's office revealed earlier Friday that Abdeslam's fingerprints and DNA were found in a Brussels apartment
raided two days earlier. One person was killed and two people escaped that operation, according to authorities.